This is very familiar though my mother is now in her 80s. I think your mother is so relatively young, less than 10 years older than me and it is worth trying to get her to change her mindset, for her sake as well as yours. As PP said, state how it affects you and your relationship with her. It may be the shake-up she needs.
But….be prepared that she may, like my own mother, not take it on board and that this is how it is going to be, and it will probably worsen as she ages.
I have had to detach in order to save my own sanity - not no contact (though I am a decent drive away), I visit, look after financial stuff, online shopping, practical stuff, try to get her to go places, have her to stay etc but I don’t feed her negativity. Non-committal ‘hmmms’ if she’s criticising other people. She is always commenting on my appearance/hair/weight/clothes but I barely respond- or say ‘well I like it’.
I am empathetic to her complaints about aging, health etc but not the bitchy, mean-spirited, complaining for the sake of it stuff. I know the increasing lack of independence etc is awful, and she would rather be able to hop in the car and shop for herself etc. I have spent many days of my life searching for the perfect item that she needs this week.
But I have gradually accepted that she will never be happy and nothing will ever please her. Her expectations of people are set impossibly high. Accepting that she won’t be pleased, makes it easier when she is not pleased. I have let go of expecting that she will change, become more grateful, more accepting of others, less negative.
Sorry this is longer than I meant to write - only you will know whether your mum has the capacity to change, it’s worth a try but be prepared, it may be you that will need to change in order to cope and stay sane. It’s really hard.